D. Yeo, J. A. Fessler, B. Kim Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States, Radiology, University of Michigan Medical School, Ann Arbor, MI, United States Introduction: The accuracy of measuring voxel intensity changes between stimulus and rest images in fMRI echo-planar imaging (EPI) data, from which brain activation maps are computed, is severely degraded in the presence of rigid head motion. In addition, EPI is sensitive to susceptibility-induced geometric distortions, especially in the mid to lower brain images. Head motion causes image shifts as well as field-map changes which result in local changes in geometric distortion. Commonly, geometric distortion correction is performed, with a static field-map, independently of image registration. This does not account for field-map changes with head motion. Previously, the concept of a concurrent motion and field-inhomogeneity correction technique using quadratic penalized least squares (QPLS) reconstruction has been introduced as an enhancement to the map slice-to-volume (MSV) motion correction scheme that accounts for inter-slice motion [1-3]. This work is an extension of [1] and evaluates the technique under more realistic simulation conditions on an entire simulated 130-volume EPI time-series.